1. Field
The disclosed embodiments generally relate to techniques for charging portable electronic devices. More specifically, the disclosed embodiments relate to a technique that uses an audio cable as an inductive charging coil for a portable electronic device.
2. Related Art
Rechargeable batteries are presently used to provide power to a wide variety of portable electronic devices, including digital music players, cell phones, PDAs, laptop computers, and cordless power tools. These rechargeable batteries are typically charged through a direct conductive connection between a transformer, which is connected to either wall power or a car battery, and the portable electronic device.
Inductive charging techniques, which operate without requiring direct conductive connections, have been developed for certain applications, such as electric toothbrushes, where the proximity to water makes a conductive connection impractical. An electric toothbrush can be recharged using a relatively small inductive receiving coil because it is typically placed in a charging stand for a long period of time (many hours) and is only used for a short period of time (about two minutes).
However, to inductively charge other types of electronic devices (such as portable media players or cell phones) at an acceptable rate, a significantly larger receiving coil is required. Providing this larger receiving coil involves either incorporating the larger receiving coil into the portable electronic device, which increases the size of the portable electronic device, or alternatively incorporating the larger receiving coil into a bulky attachment to the portable electronic device.
Hence, what is needed is a technique for inductively charging portable electronic devices without the above-described problems.